Rozhen Observation Calendar

Which nights are best for a target over the coming weeks. The astronomy mark (darkness × altitude × Moon) is computed for every night; the weather and the overall mark exist only where Open-Meteo has a forecast (the next four days) or ERA5 history (past nights) — the rest is honestly blank.

2044-09-18astronomy score per night — click a bar for that night2044-10-17

night of	weather	overall	best window	highest	dark h	Moon	Moon sep.
2044-09-18 Sun	—	unknown	—	50.1° 14:00	8.56	8%	42.5°
2044-09-19 Mon	—	unknown	—	50.1° 13:55	8.61	3%	28.5°
2044-09-20 Tue	—	unknown	—	50.1° 13:55	8.67	0%	15.3°
2044-09-21 Wed	—	unknown	—	50.1° 13:50	8.72	0%	6.9°
2044-09-22 Thu	—	unknown	—	50.1° 13:45	8.77	3%	15.4°
2044-09-23 Fri	—	unknown	—	50.1° 13:40	8.82	7%	27.8°
2044-09-24 Sat	—	unknown	—	50.1° 13:35	8.87	13%	40.3°
2044-09-25 Sun	—	unknown	—	50.1° 13:35	8.92	21%	52.7°
2044-09-26 Mon	—	unknown	—	50.1° 13:30	8.97	29%	64.8°
2044-09-27 Tue	—	unknown	—	50.1° 13:25	9.02	38%	76.7°
2044-09-28 Wed	—	unknown	—	50.1° 13:20	9.07	48%	88.5°
2044-09-29 Thu	—	unknown	—	50.1° 13:15	9.11	57%	100.3°
2044-09-30 Fri	—	unknown	—	50.1° 13:15	9.16	66%	112.1°
2044-10-01 Sat	—	unknown	—	50.1° 13:10	9.21	75%	123.9°
2044-10-02 Sun	—	unknown	—	50.1° 13:05	9.26	83%	135.9°
2044-10-03 Mon	—	unknown	—	50.1° 13:00	9.31	90%	148.1°
2044-10-04 Tue	—	unknown	—	50.1° 12:55	9.35	95%	160.3°
2044-10-05 Wed	—	unknown	—	50.1° 12:55	9.4	99%	171.1°
2044-10-06 Thu	—	unknown	—	50.1° 12:50	9.45	100%	169.6°
2044-10-07 Fri	—	unknown	—	50.1° 12:45	9.49	99%	157.6°
2044-10-08 Sat	—	unknown	—	50.1° 12:40	9.54	96%	144.2°
2044-10-09 Sun	—	unknown	—	50.1° 12:40	9.58	90%	130.5°
2044-10-10 Mon	—	unknown	—	50.1° 12:35	9.63	82%	116.5°
2044-10-11 Tue	—	unknown	—	50.1° 12:30	9.67	72%	102.4°
2044-10-12 Wed	—	unknown	—	50.1° 12:25	9.72	61%	88.3°
2044-10-13 Thu	—	unknown	—	50.1° 12:20	9.76	50%	74.3°
2044-10-14 Fri	—	unknown	—	50.1° 12:20	9.81	39%	60.3°
2044-10-15 Sat	—	unknown	—	50.1° 12:15	9.85	28%	46.4°
2044-10-16 Sun	—	unknown	—	50.1° 12:10	9.89	18%	32.7°
2044-10-17 Mon	—	unknown	—	50.1° 12:05	9.93	11%	19.5°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2044-09-18&days=30"
curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&days=30&format=csv" -o m31-calendar.csv

One row per night: score_astronomy always, score_weather / score only where a forecast or history exists (null otherwise, with weather_source saying which), best window, dark hours, Moon illumination and separation, transit. 7–60 nights. Errors: 400 with invalid_date or target_unresolved. Results are cached for six hours; calculation version 2026-10-10.1.